Process for making a computer tower chassis using modules

ABSTRACT

A computer tower chassis (10) has a base system unit (20) and a main circuit board subassembly (30). The base system unit (20) includes base system frame (200) having a front panel (21) and rear panel (26) and supporting frame (201, 202, 203, 204, and 205) therebetween. Disk (22), control panel (23), power supply (24), and floppy drives (29) mount to the base system unit (20). The main circuit board subassembly (30) includes main circuit board (31), input/output board and cable (32), speaker and cable (33), fan assembly and cable (35), keyboard cable (36), expansion card (37) and expansion card guides (38) and (39). Main circuit board subassembly (30) fits within and adjacent to base system unit (20), with chassis cover (40) surrounding both modules. The modular design allows for safer and more efficient manufacturing and handling.

This application is a divisional of application Ser. No. 07/623,589,filed Dec. 7, 1990 and entitled "Modular Personal Computer," now U.S.Pat. No. 5,159,528, issued Oct. 27, 1992.

TECHNICAL FIELD OF THE INVENTION

This invention relates to a method and apparatus for a manufacturer toassemble electronic hardware for an electronic system and moreparticularly to a method and system for assembling a computer towerchassis.

BACKGROUND OF THE INVENTION

Computer systems, particularly personal computer systems, include a boxor chassis that contains the electronic hardware of the centralprocessing unit and communication cables for transferring data betweenterminals and other data communications components. Typically, themanufacture of the chassis includes forming a metal support frame toreceive the electronic hardware and placing a cover around theelectronic components and the support frame. Although a personalcomputer chassis is sufficiently small that one person usually can pickit up, a fully assembled unit weighs approximately 70 pounds.

As factory assembly of a personal computer chassis takes place, thechassis increases in weight and becomes more difficult to maneuver alongan assembly line. Picking up and moving the heavy computer chassis canpresent safety and handling problems for factory workers. If a methodand apparatus existed to preassemble major portions of the computerchassis prior to full assembly of the chassis itself, the weight of thechassis could be distributed among the major modular portions. Thiswould eliminate problems associated with moving and handling thecomplete tower chassis until final assembly.

A fully assembled tower chassis includes a main circuit board thatcomprises a central processing unit and other communications and dataprocessing electronic components as well as power conversion anddistribution components that operate the computer. If it were possibleto separate a significant portion of the tower chassis electroniccomponents in a modular fashion to concentrate repair efforts on a majormodular section, handling safety problems associated with these repairswould also be minimized.

Related problems exist with respect to efficiency in manufacturing thecomputer chassis. For example, known tower chassis assembly methodsbegin with the chassis structural frame. Throughout the computerassembly, all electronic and mechanical components of the tower chassisare installed on the structural frame. As components on the structuralframe become more densely packed together, it becomes increasinglydifficult for more than one worker to assemble additional components onthe structural frame. As a result, the manufacturing process slows asthe tower chassis becomes more densely packed with mechanical andelectronic components.

If a system and method existed to allow workers to first assemble majorportions of the computer tower chassis and then connect the majorportions together, more than one worker could easily assemble theseparate major portions. This would increase computer tower assemblyrates and ultimately increase the manufacturing process efficiency.

Consequently, there is a need for a method and apparatus that minimizesthe safety, handling, and assembly problems associated withmanufacturing a computer chassis. There is a need for an apparatus thatallows repair personnel to safely and efficiently disassemble a computertower chassis for the purpose of isolating and repairing defectivecomponents of the computer tower chassis.

There is a need for a method and apparatus that allows more than onefactory worker to simultaneously assemble portions of a computer towerchassis.

SUMMARY OF THE INVENTION

The present invention provides a computer tower chassis and chassismanufacturing process which overcome the problems and satisfy the needspreviously considered. The method and apparatus allow modular assemblyof major portions of the computer tower chassis during the manufacturingprocess, thereby allowing manufacture of major portions of the towerchassis followed by assembly of the major modular portions just prior tofinal electronic component testing and burn in.

The computer tower chassis of the present invention accomplishes theseobjectives by separating the tower chassis into a base system unit and amain circuit board subassembly. The base system unit provides the majorstructure for the tower chassis and includes floppy drives and harddrives, a control panel, a power supply, and appropriate cables. Themain circuit board assembly includes the principal electronic componentsof the computer tower chassis such as the main circuit board itself, theinput/output boards and cables, battery pack and cable, speaker assemblyand cables, fan assembly and cables and all required expansion boards.

In the manufacture of the computer tower chassis, the base system unitand the main circuit board subassembly can be manufactured at the sametime (i.e., in parallel). When the base system unit and main circuitboard subassembly are complete, they can be joined together to form acomputer tower chassis sufficiently complete for final testing and burnin. Thereafter, the tower chassis cover is placed around the chassis tocomplete the manufacturing process. The base system unit has astructural frame and support members associated to receive the maincircuit board subassembly and to structurally support both the maincircuit board subassembly, as well as the components that attach to thebase system unit.

If, as a result of testing, one or more components on the base systemunit or the main circuit board subassembly are shown to be defective,the defective portion can be promptly replaced by a fully functionalmodular portion. By swapping out the defective module with asatisfactory one, the assembly process can continue to completion forthat particular tower chassis.

Placing the primary electrical and mechanical portions of the towerchassis on the base system unit and the electronic components on themain circuit board subassembly divides the computer tower chassisweight. As a result, until final assembly, the module that a workerhandles weighs significantly less than the complete tower chassis. Thisresults in safer and more easily maneuverable components prior to finalassembly.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and furtheradvantages thereof, reference is now made to the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 shows an exploded view of the modular tower chassis of thepresent invention and its associated cover;

FIG. 2 is an exploded perspective of the base support unit of themodular tower chassis of the present invention;

FIG. 3 is an exploded perspective view of the main circuit boardsubassembly of the present invention; and

FIG. 4 illustrates the relative size of a computer tower chassis as itprogresses along an assembly line to show some of the advantages of thepreferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates the modular design of the present invention. Computerchassis 10 includes the base system unit 20, adjacent to which fits maincircuit board subassembly 30. Once base system unit 20 and main circuitboard subassembly 30 join to form computer tower chassis 10, cover 40fits over it to protect computer tower chassis 10. Main circuit boardsubassembly 30 has keyboard cable 36 and rear expansion card guides 39which fit through openings 27 and 28 on the rear portion 26 of basesystem unit 20.

FIG. 2 shows a more detailed and exploded perspective view of basesystem unit 20 according to the preferred embodiment of the presentinvention. Base system unit 20 includes support frame 200 whichcomprises front support plate 21 and rear support plate 26. Betweenfront support plate 21 and rear support plate 26 are structural beams201, 202, 203, 204 and 205. Within support frame 200 are variouscomponents that form base system unit 20. Hard drives 22 and powersupply 24 mount within base system unit 20. Attaching to and extendingthrough base system unit 20 are control panel 23 and floppy drives 29.Fasteners 25 securely hold each of these units to base system unit 20and attach main circuit board subassembly 30 to base system unit 20.

FIG. 3 provides an exploded perspective view of main circuit boardsubassembly 30 in the preferred embodiment of the present invention.Main circuit board subassembly 30 includes the subassembly plate 300having integral thereto rear panel 302 and front subassembly panel 301.Front subassembly panel 301 includes the front expansion board guides38. Rear panel 302 includes rear expansion slots 39. Main circuit board31 mounts to subassembly plate 300 so that expansion cards 37 mayconnect within front expansion card guides 38 and rear expansion slots39. Input/output board and cable 32 mounts to subassembly plate 300.Speaker assembly and cable 33 and fan assembly and cable 35 mount tofront subassembly panel 301. Battery pack and cable 34 and keyboardcable 36 mount to and through rear subassembly panel 302. Numerousfasteners 305 secure the above components to main circuit boardsubassembly plate 300.

In the design of FIGS. 2 and 3, principally mechanical and electricalcomponents attach to base system unit 20. These all attach to the frontand rear panels of base system frame 200 in a way that providessufficient room for subsequent insertion of the completed main circuitboard subassembly 30. Main circuit board subassembly 30 has variouscomponents that penetrate through base system frame 200 for electricaland electronic external connections. These components include rearexpansion slots 39 and keyboard cable 36. Base system frame 200 providesopenings 27 and 28 to permit connection to rear expansion slots 39 andkeyboard connection 36.

The design of main circuit board subassembly 30 is similar, but notidentical to the interior portion of the High Profile chassismanufactured by CompuAdd Corporation of Austin, Tex., stock #15000-3.This is a known configuration for the placement of main circuit board 31and the associated expansion cards 37 and front expansion card guides 38and rear expansion slots 39, as well as the other components of maincircuit board subassembly 30. The technical advantage associated withthis design is that the modular approach to main circuit boardsubassembly 30 and base system unit 20 can be implemented by factoryworkers trained to assemble the CompuAdd High Profile chassis andsimilar designs. As a result, implementing the modular design ispossible with minimal additional training of factory workers.

Because the basic system unit and main circuit board subassembly 30 aremodular in design, they can be assembled separately until they arefinally joined. For example, one assembly line in a factory couldassemble base system unit 20, including power supply 24, hard drives 22,floppy drives 29 and control panels 33. Another assembly line in thesame or a different factory could assemble main circuit boardsubassembly 30, including main circuit board 31, input/output board andcable 32, speaker assembly and cable 33, fan assembly and cable 35,input/output board and cable 32, and keyboard cable 36. The result wouldbe a separate base system unit 20 and main circuit board subassembly 30to join together for final system testing and burn in. Thereafter, cover40 would be placed on the completed computer tower chassis to make thechassis ready for shipment. With the distributed weight made possible byhaving one assembly line assemble the system unit 20 and anotherassembly line assemble the main circuit board subassembly 30, theproblems of safely handling a complete computer tower chassis areminimized. Although the weight of the completed computer tower chassisis distributed between base system unit 20 and main circuit board ofsubassembly 30, the weight would not necessarily be distributed evenly,because the number of hard drive devices in base system unit 20 canvary.

Although it is shown that the base system unit 20 and main circuit boardsubassembly 30 have a particular set of components that join together ineach respective module in the preferred embodiment of the presentinvention, there may be other combinations of respective components aswell as additional components that could be included in each of theassemblies for modular fabrication. In particular, base system unit 20may include multiple hard drive devices and up to five half height mediadevices in the preferred embodiment. The four bay external drive holdercan, for example, accommodate a floppy drive, a tape backup unit, a CDROM device, and/or a hard drive. Combinations of these are within thescope of the present invention. Moreover, depending on the size andcomplexity of the computer tower chassis, it may be advantageous for thechassis to comprise more than two separately assembled modules.Additionally, the main circuit board subassembly 30 of the presentinvention could use various styles of main circuit boards and numerousconfigurations of expansion boards.

The configuration of components that mount to base support frame 200depends on the design of the computer tower chassis. However, for thepurposes of the present invention, the configuration must permitseparating and joining of the main circuit board subassembly 30 frombase system unit 20. Additionally, this arrangement of the individualsupport frames 201, 202, 203, 204 and 205 may be varied according to theparticular design requirements of both base system unit 20 andinterconnection requirements of main circuit board subassembly 30. Easywithdrawal of expansion cards 37 from main circuit board subassembly 30,without the need to disassemble main circuit board subassembly 30 frombase system unit 20, is another design consideration of the presentinvention. In other words, a modular design of base system unit 20 andmain circuit board subassembly 30 need not adversely affect theinterchangeability of expansion cards with the main circuit board 31.

FIG. 4 illustrates an important aspect of the preferred embodiment ofthe present invention. Along assembly lines 41 and 42 travel maincircuit board subassembly 30 and base system unit 20, respectively. Atstation 44, for example, main circuit board subassembly 30 and basesystem unit 20 may be joined to result (after placement of cover 40) incompleted tower chassis 10. Tower chassis 10 joining in this mannerachieves many of the purposes of the present invention.

Although the invention has been described with reference to the abovespecific embodiments, this description is not meant to be construed in alimiting sense. Various modifications of the disclosed embodiment, aswell as alternative embodiments of the invention will become apparent topersons skilled in the art from reference to the above description. Itis further contemplated that the claims will cover such modificationsand fall within the true scope of the invention.

What is claimed is:
 1. A method of assembling a modular personalcomputer, comprising:installing a control panel, a power supply, and atleast one disk drive selected from the group of hard drives and floppydrives onto a base system unit including a support frame having a frontsupport plate and a rear support plate, the rear support plate beingspaced from the front support plate, at least one structural beamconnecting the front support plate to the rear support plate; removablyinstalling a main circuit board onto a main circuit board assemblyincluding a subassembly plate having front and rear edges, a frontsubassembly panel having an orifice therethrough attached to the frontedge of the subassembly plate, a rear assembly panel having a pluralityof orifices therethrough attached to the rear edge of the subassemblyplate, at least one front expansion board guide attached to the frontsubassembly panel, at least one rear expansion slot attached to the rearsubassembly panel; removably connecting at least one expansion cardhaving front and rear ends to the main circuit board whereby the frontand rear ends of the expansion cards removably connect to the frontexpansion board guides and to the rear expansion slots, respectively;installing an input/output board having an input/output cable onto thesubassembly plate; installing a speaker assembly having a speaker cableand a fan assembly having a fan cable in the orifice of the frontsubassembly panel; installing a battery pack having a battery pack cableand a keyboard cable onto the rear subassembly panel, the battery packcable and the keyboard cable extending through respective orifices inthe rear subassembly panel; attaching the main circuit board assembly tothe base system unit; and removably installing a cover over the basesystem unit and the main circuit board assembly.